Universal, asynchronous transmitter/receivers (UARTs) are interface circuits, generally in the form of integrated circuit chips, which are disposed between a data providing circuit, such as, for example, a personal computer (PC) and a modem to provide parallel-to-serial and serial-to-parallel data conversion. Although UARTs can be stand-alone devices, they also can be incorporated into the communication port of a more complex integrated circuit chip. UARTs generally include an oscillator and a crystal to synchronize data conversion with a fairly precise oscillator frequency, which facilitates asynchronous communication between two remotely disposed UARTs. The purpose for having a crystal controlled oscillator is to ensure that the frequency of a specific UART is within a defined limit specified for UART operation. The use of a free-running oscillator will typically not be acceptable due to temperature drift, manufacturing tolerances, etc. Of course, crystals are typically external devices, thus requiring a more complex assembly.